NAME: Norwalk virus
SYNONYM OR CROSS REFERENCE: Acute viral gastroenteritis, Norwalk-like disease, epidemic viral gastroenteritis, acute infectious nonbacterial gasteroenteritis, viral diarrhea, epidemic diarrhea and vomiting, winter vomiting disease, epidemic nausea and vomiting
CHARACTERISTICS: Caliciviridae; round, non-enveloped, 27-32 nm virion; single-stranded positive - sense RNA
PATHOGENICITY: Abrupt onset of diarrhea, vomiting, non-bloody diarrhea and abdominal cramps; 25-50% of affected persons report myalgias, malaise, headache, nausea and low-grade fever; illness usually resolves within 24-48 hours; fatality is associated with electrolyte imbalance; symptoms can persist for up to several weeks; higher risk of symptomatic infection in individuals with preexisting levels of antigen-specific antibodies have been documented
EPIDEMIOLOGY: Worldwide and common; affects mainly older children and adults; frequent outbreaks in camps, schools, nursing homes, cruise ships and areas with contaminated drinking and swimming water; outbreaks are limited to 1-2 weeks
HOST RANGE: Humans
INFECTIOUS DOSE: Not known
MODE OF TRANSMISSION: Principally by fecal-oral route; other documented sources include water, food (particularly shellfish and salads), aerosol and fomites
INCUBATION PERIOD: From 10-60 hours; usually 24-48 hours
COMMUNICABILITY: Communicable during the acute stage of the disease; up to 48 hours after resolution of symptoms; presymptomatic shedding has been implicated in epidemiological studies
RESERVOIR: Humans
ZOONOSIS: None
VECTORS: None
DRUG SUSCEPTIBILITY: No specific antivirals
SUSCEPTIBILITY TO DISINFECTANTS: Susceptible to 1% sodium hypochlorite, 2% glutaraldehyde
PHYSICAL INACTIVATION: Resistant to pH5-10, ether, acid; survives at 60° C for 30 minutes
SURVIVAL OUTSIDE HOST: Stability unknown; found in contaminated water supplies, lakes
SURVEILLANCE: Monitor for symptoms; confirm by RIA; conclusive diagnosis by EM examination of stool samples
FIRST AID/TREATMENT: No specific therapy other than electrolyte and fluid replacement
IMMUNIZATION: None available
PROPHYLAXIS: None available
LABORATORY-ACQUIRED INFECTIONS: None reported to date
SOURCES/SPECIMENS: Stool specimens
PRIMARY HAZARDS: Ingestion; exposure of the mucous membranes to infective aerosols
SPECIAL HAZARDS: None
CONTAINMENT REQUIREMENTS: Biosafety level 2 practices and containment equipment for all activities involving the virus or any infectious or potentially infectious body fluids or tissues
PROTECTIVE CLOTHING: Laboratory coat; gloves when skin contact with infectious materials is unavoidable
OTHER PRECAUTIONS: None
SPILLS: Allow aerosols to settle; wearing protective clothing gently cover the spill with absorbent paper towel and apply 1% sodium hypochlorite starting at the perimeter and working towards the centre; allow sufficient contact time (30 min) before clean up
DISPOSAL: Decontaminate all wastes before disposal; steam sterilization, chemical disinfection, incineration
STORAGE: In sealed containers that are appropriately labelled
Date prepared: March, 2001
Prepared by: Office of Laboratory Security, PHAC
Although the information, opinions and recommendations contained in this Material Safety Data Sheet are compiled from sources believed to be reliable, we accept no responsibility for the accuracy, sufficiency, or reliability or for any loss or injury resulting from the use of the information. Newly discovered hazards are frequent and this information may not be completely up to date.
Copyright ©
Health Canada, 2001
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